Add article about installing RDO with Ceph

Change-Id: I277d256bc44957bcbb6ba8373bf5fe514070410e

docs/deploy/index.md

@@ -23,6 +23,10 @@ Puppet OpenStack modules provide puppet-based per-service modules intended to pr
 
 [This project](https://github.com/openstack/openstack-ansible) has partial support for RDO as provider for binary installations in CentOS, hovewer it's not tested in our CI. Main documentation can be find [here](https://docs.openstack.org/openstack-ansible/latest/), there is also available a [deployment guide](https://docs.openstack.org/project-deploy-guide/openstack-ansible/latest/).
 
+## RDO with Ceph as storage
+
+Under this [article](./install-with-ceph.md) you can find instructions how to install RDO with Ceph as storage.
+
 
 ## RDO on OKD - experimental
 

docs/deploy/install-with-ceph.md

@@ -0,0 +1,38 @@
+---
+title: Install with Ceph
+category: documentation
+authors: jcapitao
+---
+
+# Install RDO with Ceph as storage
+
+## The Ceph releases used for each RDO release
+
+| RDO Release | Ceph Release |
+| ------ | ----- |
+| Dalmatian | Reef |
+| Caracal | Reef |
+| Bobcat | Reef |
+| Antelope | Quincy |
+| Zed | Quincy |
+| Yoga | Pacific |
+
+## Enable EPEL repository for Ceph Reef
+
+Since the Ceph Reef release, the [CentOS Stream Storage SIG](https://sigs.centos.org/storage/) decided to pull some dependencies from the EPEL repo instead of rebuilding and providing them itself.<br>
+As a result, the EPEL repository needs to be enabled on the target host in order to be able to install `centos-release-ceph-reef` sucessfully.<br>
+However, enabling the EPEL repository with the default parameters might conflict with the RDO repository (i.e duplicate packages with different NVR). To avoid this conflict, if you plan to install RDO OpenStack and Ceph services in the same host, you must set the EPEL repository with a lower priority and include only the packages needed, see below:
+
+````
+  $ sudo dnf update
+  $ sudo dnf install 'dnf-command(config-manager)'
+  $ sudo dnf config-manager --enable crb
+  $ sudo dnf install epel-release
+  $ sudo dnf config-manager --disable epel-next
+  $ sudo dnf config-manager --disable epel-cisco-openh264
+  $ sudo dnf config-manager --setopt epel.priority=100 --save epel
+  $ sudo dnf config-manager --setopt epel.includepkgs="libarrow*,parquet*,python3-asyncssh,re2,python3-grpcio,grpc*,abseil*" --save epel
+  $ sudo dnf install centos-release-ceph-reef
+  $ sudo dnf install ceph
+````
+  Note: installing `centos-release-ceph-reef` is not needed if `centos-releae-openstack-bobcat` is already installed (i.e it's a requirement).